Knucklebus

Maybe I'm just sensitized to it but I think my car has a speed-related roar. It starts about 25MPH and gets higher pitched. When accelerating, the engine noise drowns it out but when braking, it can be heard growling all the way down to 10-15MPH.

I first suspected a wheel bearing but it does not get worse in a left or right corner, my preferred method of picking a side. Also, with the windows down, wind noise is louder and drowns out this sound. I've had my wife drive it while I'm hanging my head out both sides and also listened in the pass-through area to see if it was coming from the trunk.

Does anyone know if I can lift all 4 wheels off the ground, disable traction control and run it up to 35MPH? That would be the quickest way to walk around it and see where the noise is coming from.

Maybe I'm being paranoid after replacing one wheel bearing a few years ago. Turning the radio up to 12 or running the AC fan on high will almost drown it out as well.

lexo98

iTrader: (2)

Run your hands across the back tires. See if you feel high and low spots.

Knucklebus

No high/low spots and they are rotated regularly. Frankly, with COVID and driving so much less, I'm not sure the car didn't do this from day 1. The bad wheel bearing was pretty loud, like driving a 4x4 truck with mud tires.

bclexus

Are you hearing the airflow rushing/roaring noise from having the seat ventilation turned? This rushing airflow noise is heard especially when leaning head forward toward steering wheel.

jgscott

iTrader: (1)

What year and miles on your GS?

Knucklebus

Definitely not. I've listened from front and rear and that is a whoosh as opposed to a roar that increases with MPH. Definitely not a constant tone nor an engine associated sound. It is something that is directly related to speed and speed only.

Which is why I asked if I can put it on a lift and disable traction control to run it up to 35 MPH.

2013 GS 350 AWD, 70K miles

bclexus

I don't see why you couldn't disable traction control and run it up to 35 mph.

Knucklebus

You never know with all the nannies they put on cars these days. A Tesla can't be moved if the batteries die.

bclexus

Yeah, agree.

It would be nice if you could strap it onto a Dyno and and have some fun with horsepower, torque and rpm numbers as you listen for what's making the roaring noise. In either case (Dyno or on a lift) you won't be able to load the suspension and bear weight on axles/hubs at the corners.

Knucklebus

I'm thinking it is not load based as I pulled some pretty aggressive left and right maneuvers to try to find out if it was one one side or the other.

Being AWD, it could be the bearing that runs through the center from the differential to the right front wheel.

GSJ350

easy way to rule out a wheel bearing is to get a laser thermometer and after a 10 min steady drive down the highway jump out and check all four corners for hub temps. Tires also wear in different patterns to create road noise that would be speed dependent. Check differentials as well but those usually create a whining noise so there is always that. My guess would be a wheel bearing even though you think its not, because the symptoms you have explained are all pointing that direction even though your tests didnt point that direction. When i was test driving GS's before i bought my 15, i drove a 13 AWD and it made a low whine and very suttle floor vibration from about 40mph and below. Grab a laser temp guage off amazon which dont cost that much as they used to and check to see if you can spot an anomaly.

Knucklebus

I have a laser temp gun. I'll give that a try. I tried to record a video but it isn't picked up very well. There is no vibration, just speed variable noise.

You can pick up the sound if you turn up the volume. I speak in a normal tone to give some perspective.

Audio (with useless video) of roar.

bclexus

Transfer Case roar/whine from 30 - 50 mph under light throttle?

► https://static.nhtsa.gov/odi/tsbs/20...96083-5448.pdf

Knucklebus

Well, missed the time and miles part of it.

I will get it up on the lift and see if I can see anything. I don't see how a mount could cause that unless it is collapsed or something. It isn't vibrating.

GSJ350

Is it more pronounced when braking?.. and does the noise have a slow pulsation or cadence to it?